On Fri, Jul 07, 2006 at 10:55:28AM -0400, Steven M. Bellovin wrote:
> Is the "real" memory allocated to Xen DomU machines paged by the Dom0
> machine?  Put another way, the machine has a certain amount of RAM.  What
> are my choices for allocation among several DomUs?  It's obviously bad to
> overcommit too much, resulting in double-paging, but am I restricted to
> the total amount of real memory in assigning memory sizes to the VMs?

Xen can only work with physical RAM. linux domains have a 'baloon' driver,
which can give some ram back for Xen when the domain doens't need that much
ram. This allows to overallocate RAM and have the domains cooperate to
put the ram where it's needed, but it's not implemented in NetBSD yet.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--